The invention relates generally to surface coating processes and is particularly concerned with a surface coating including rubber material such as silicone rubber and similar rubber materials.
Surface coatings are often applied to fabrics and other surfaces to improve their qualities, for example to provide improved waterproofing and insulating properties. In the case of outdoor clothing and sport wear, any surface coating must be sufficiently flexible and lightweight so as not to reduce the wearer's mobility, while providing the desired thermal insulation. In many coating materials, the thickness of material required to provide the necessary insulation will undesirably reduce the material flexibility.
A wide range of impermeable materials are known in the art suitable for use in the fabrication of special clothing intended to protect the wearer in cold, wet, or otherwise inhospitable environments. The well-known wet suit is a tightly fitting garment worn by cold-water swimmers as protection against the cold temperatures. The wet suit is so-called because it is normally flooded and performs its function by holding a layer of water against the skin of the swimmer. This layer of water is heated to body temperature by body heat and insulates the swimmer from the ambient water temperature because the wet suit prevents circulation of ambient water against the swimmer's skin.
The drysuit is also used by swimmers and divers for protection against the cold water temperature but, unlike the wet suit, is not flooded and performs by insulating the swimmer from the cold water while sealing against flooding. The drysuit generally provides auxiliary heating means and/or thicker insulation means than is necessary with the wet suit because the drysuit has no provision for holding an insulating layer of warm, static water against the swimmer's skin.
A biohazard suit is known in the art for protecting the wearer against exposure to hazardous biological material in the environment. The biohazard suit is sealed against flooding by air or water and attaches to sealed boots, helmet and gloves to completely isolate the wearer from the hazardous environment.
The general bodysuit class of protective wear includes the biohazard suit, the wet suit, the drysuit, and other similar protective wear having requirements for high thermal insulation, low permeability, precise mechanical fit on thee body of the wearer, non-compressibility of the coating under pressure and resistance to accidental breaks and leakage. Other important requirements for this bodysuit class of protective wear is flexibility for wearer mobility, fire resistance, zero buoyancy, suitability for embedded wiring and sensors, and visibility (coloration).
The drysuit and wet suit known in the art consist of layers of neoprene foam rubber or other types of rubber commonly used in drysuits stitched together with appropriate seals or water-tight zippers to permit the wearer to don and doff the suit. The neoprene and rubber foam bodysuit has several well-known disadvantages. The neoprene foam seams are prone to leakage. The neoprene rubber is highly flammable, is prone to UV degradation, is easily breached by abrasion, and is restrictive of wearer mobility because of the thickness required for acceptable thermal insulation values. Moreover, the neoprene foam wet suit is highly buoyant, requiring inconvenient weight belts in underwater use. Similar disadvantages are known for other neoprene and organic rubber foam bodysuits fabricated for use as drysuits and other related applications.
To obtain satisfactory thermal insulation using only neoprene foam rubber, most bodysuits known in the art become so thick that the mobility of the wearer is seriously impaired. Also, the well-known mechanical vulnerability of neoprene foam-rubber sheets results in frequent unintentional breach of the bodysuit by abrasion and tearing.